That's the point. If you think a T is incompetent, there's no point in asking them for a referral. But if you think the T is competent, but for other reasons not a good fit, then a referral will probably also be competent. Whether or not that T will be a good fit, is up to you to determine by meeting with them. I wouldn't expect a T to be able to predict that for me.

I think it also depends upon how the referring Ts practice: are they professionally active? Are they involved in professional organizations and groups? If it's a solo T who isn't involved outside the practice, the ability to refer is going to be compromised, as is the T's professional knowledge of another T.